One possibility is that it’s how you phrase things? Everything seems fine here but people tend to write and speak differently, so just throwing out a possibility here.
I used to say essentially “not my fault” a lot as a kid (it was a kind of deflection that I resorted to instead of actually dealing with stuff), and my mom called me out on it once, which caused a huge shift in how i thought about communication from then on. See, sometimes it was my fault, and other times it wasn’t, but that doesn’t really matter a lot in a conversation, so I started kinda taking a mental step back to consider what I was about to say would actually accomplish in the conversation, or how it might be perceived by others, and it became clear to me that I had some other bad conversational habits as well that escalated situations when they didn’t need to.
It might not be easy to detect all of them at once, but just getting into the mindset of thinking about this stuff might help. Hopefully this technique isn’t why I’m anxious these days :P
Edit: Also some subjects are sore as you experienced with your unemployed friend, so having this habit of taking a step back might have helped with realizing that in advance. It’s not always doable of course, you can’t know everything.
Its certainly harder to explain over text since we can’t hear your tone. Do you put in a lot of effort when you speak ? Does talking come naturally, or do you spend a lot of energy trying to be polite ?
Without knowing exactly what you said its hard to know if this reflects more on your friend than you. Apologizing should be fine, so the issue is either how you apologized or your friend. Also a two day argument is a long argument. Who kept it going? Who would bring it up first?
Edit: I see in one comment that you are autistic. Have you talked to your friends and family about what this means in a conversation ? At some point its on them, honestly.